The long-range goal of the research is the elucidation of long range structure of DNA in certain prokaryotic and eukaryotic chromosomes and the determination of the molecular interactions which organize this structure. Specifically, we are investigating the function of certain prokaryotic proteins in restraining supercoils in DNA of Escherichia coli cells. Molecular interactions which organize DNA loops and domains of supercoiling are also being investigated. The role of certain non-histone chromosomal proteins in DNA packaging of human and Drosophila melanogaster chromosomes is also under study.